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    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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    <script>
        function isPrime(n){
            let flag = true;
            for(let i = 2;i * i <= n;++i)
                if(n%i == 0){
                    flag = false;
                    break;
                }
            return flag;
        }
        console.log('9'+isPrime(9));
        console.log('7'+isPrime(7));

    </script>
</body>
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